将d:\java目录下的所有.java文件复制到d:\jad目录下，并将原来文件的扩展名从.java改为.jad

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FilenameFilter;
import java.io.InputStream;
import java.io.OutputStream;

public class Jad2Java {

public static void main(String[] args) throws Exception {
File srcDir = new File("d:/java");
if (!(srcDir.exists() && srcDir.isDirectory()))
throw new Exception("目录不存在");
File[] files = srcDir.listFiles(new FilenameFilter() {

public boolean accept(File dir, String name) {
return name.endsWith(".java");
}

});

System.out.println(files.length);
File destDir = new File("d:/jad");
if (!destDir.exists())
destDir.mkdir();
for (File f : files) {
FileInputStream fis = new FileInputStream(f);
String destFileName = f.getName().replaceAll("\\.java{1}quot;, ".jad");
FileOutputStream fos = new FileOutputStream(new File(destDir,
destFileName));
copy(fis, fos);
fis.close();
fos.close();
}
}

private static void copy(InputStream ips, OutputStream ops)
throws Exception {
int len = 0;
byte[] buf = new byte[1024];
while ((len = ips.read(buf)) != -1) {
ops.write(buf, 0, len);
}

}
}